The Role of Irreversible Forces On Deterministic Lateral Displacement and Other Microfluidic Separation Methods

When a suspended sphere moves deterministically and at low Reynolds number around a circular obstacle it typically reaches extremely small separation gaps, leading to the occurrence of irreversible particle-obstacle interactions. We show that such interactions explain the behavior observed in two popular separation methods in microfluidics, pinched flow fractionation (PFF) and deterministic lateral displacement (DLD).